Retail stores offer goods for sale and need to provide customers with information on item pricing. Price labels typically provide information describing an item, the price for that item, and a machine readable code for the item, typically in UPC bar code format. The price of items often changes rapidly, requiring that printed retail labels be manually changed. Items that are on sale often have a larger secondary label, called a shelf-talker, that highlights items on sale for customers. The process of writing and changing retail pricing is costly, primarily in the labor required to replace tags. Systems have been proposed to address the problem of using digital data transmission to electrically changeable retail labels known as Electronic Shelf Labels (ESL).
U.S. Pat. No. 5,448,226, issued Sep. 5, 1995 to Failing, Jr. et al. describes an ESL system having a plurality of electronic price labels fitted into rails. The rails provide power and communication to each label. Connection to the rail can be provided through direct electrical connection to a conductor in the rail or a radio frequency (RF) interface. The label can be powered though direct electrical connection to power conductors in the rail, a battery or solar cell. Such a system requires expensive complex electronic and communication structures.
U.S. Pat. No. 6,186,555, issued Feb. 13, 2001 to Rawlings describes paper shelf-talkers that can be attached to conventional paper shelf labels to identify items on sale. Adhesive strips are applied to a perforated substrate that is printed to align text with the adhesive label. Attaching such a shelf-talker to a label requires the assembly to be discarded when pricing is changed. U.S. Pat. No. 5,771,005, issued Jun. 23, 1998 to Goodwin III describes an auxiliary electronic display that can be attached to an electronic price label (sic). The auxiliary display acts as an electronic shelf talker to identify special prices on goods.
U.S. Pat. No. 6,130,603, issued Oct. 10, 2000 to Briechle provides a good reference for current Electronic Shelf Labels. Independent modules contain a power supply, antenna and controller. The controller is attached to a conventional liquid crystal display that requires periodic refreshing to maintain an image. Displays in ESLs currently display data on simple seven segment numeric data. An internal power supply expends about half its power maintaining the display image and the other half of the power maintaining the RF link. Such displays have limited display resolution, and must incorporate expensive and bulky controller and transmission electronics. Such displays further must incorporate a power supply which further increases cost and size.
U.S. Pat. No. 5,751,257 issued May 12, 1998 to Sutherland shows an electronic shelf label having first and second substrates. Sutherland omits the expensive controller and power portions of the ESL, using a programming device translated across a series of pins and to write segments of an electronic display formed between the two glass substrates. The Sutherland apparatus requires the device to be positioned at a specific initial position, and translate specific sequence and rate to update the shelf tag. The information displayed in the Sutherland apparatus is limited to low resolution images.
There is a need therefore for an improved display system having a low cost rewritable shelf label with high resolution.